In The Sims 3, we made many additions and improvements to the lovable and quirky beings we call Sims. By far, my favorite of those is our character traits system, and I know I’m not alone – it has captured the hearts and minds of our players, too – often even more than our largest feature: the seamless, living neighborhood. So I wanted to describe the thinking that led us to the traits design, and some of the interesting choices and observations we made along the way.

Personality in The Sims and The Sims 2

First, a little background. In The Sims and The Sims 2, personalities were chosen on a ten-point scale along five different personality characteristics:

The Sims

The Sims 2

In The Sims, personality affected the choices a Sim made on their own, affected rates of skill gain, and also altered the speed a Sim’s needs would deplete. For example, a Sim with a high playful score would have their fun drop quickly, causing the Sim to do more fun things than normal.

In The Sims 2, we expanded the system to add special behaviors for specific ranges of personality. The 0-3 range was considered “low” and 8-10 points was considered “high.” Both came with unique animations and interactions for the Sims. Anything in between (4-7 points) was considered neutral, and usually did not have any special animations or interactions. For example:

Sloppy Sims (0-3 points) would create puddles when taking showers, make objects dirty more quickly, and could eat from the trash.

Neat Sims (8-10 points) could get fun by cleaning objects, and could even clean objects that weren’t yet visibly dirty, causing those objects to take much longer to get dirty.

In Between (4-7 points) didn’t have special animations or interactions. They only had varying need decays, skill rates, and autonomy behaviors.

All personalities worked this way. As you can see, we bundled the special content toward the extremes.

Inspiration and Philosophy for Traits

The problem we found as we were implementing personalities on The Sims 2 was that we couldn’t reasonably create enough special animation and interaction content to make each notch of the 0-10 scale feel interesting.

Additionally, players didn’t understand that there would only be a nominal difference between, say, a 2-point and a 3-point Sloppy Sim, but a huge difference between a 3-point Sloppy Sim and a 4-point Sloppy Sim. We didn’t make that clear in the UI, so players had to learn this from strategy guides and Sims wikis.

Around the time we began designing The Sims 3, I’d been reading a lot about screenwriting, and noticed that in screenplays, characters often have a few glaringly distinct traits. There’s no fuzziness about them:

We used this approach as inspiration on The Sims 3, and developed a philosophy of doing away with the continuous aspect of personality. Instead, we wanted to take the extremes from The Sims 2 and package that fun content into discrete bundles of behavior, which we dubbed Traits.

A Friendly Sim (probably waving to Bella)

Scouring the Personal Ads (For Science!)

Now, how would we begin to figure out which traits we wanted? One of the first days we brainstormed traits, my boss called me into his office (Matt Brown, now of Blizzard). Quirky genius that he was, he sat me down and pointed to his monitor, which was littered with personal ads and dating websites. The idea was to see exactly how people described themselves. People said things like the following, which are from real personal ads:

Proud

Loves Poetry and Chocolate

Down to Earth

Enjoys the Outdoors

Passionate

Romantic

Appreciates Classical Music

Athletic

Walking the Fine Line between Human Being and Deity

Articulate

Friendly

Trustworthy

Mid-Life Crisis Sufferer

Non-Smoker

Smoking Enthusiast

Penchant for Whistling

Likes Kissing

Reclusive

Adventurous

If you play The Sims 3, you’ll notice some of these from the game with slightly altered names: Loves the Outdoors, Hopeless Romantic, Athletic, Friendly, and Loner. And although Mid Life Crisis didn’t make sense as a trait, we used it as a lifetime happiness reward which could be used to swap traits mid-game.

Seinfeld, The Simpsons, and Arrested Development

Then we locked the design team in a room and made a list of the interesting characters we knew from TV, movies, and books. We filled entire whiteboards with names, then scrawled the prominent traits of those characters in any whitespace we could find. Due to the wonders of technology, I was able to dig up a piece of one of those brainstorms. I know it looks like we had an angry chimp scribbling these down, but hey… it’s hard to keep a chimp happy all the time:

One segment of a whiteboard brainstorm of characters and their prominent traits, circa 2005. (Note that there is no spatial relationship between the traits and the characters – we were cramming stuff in everywhere.)

In the end, a handful of fun traits in The Sims 3 were inspired by some of our favorite characters. Here are four:

Frugaland Mooch: For both of these, we had George Costanza in mind. Remember the episode where he insists on the cheapest wedding invitations in the store, and his fiancée dies from licking the cheap toxic glue on all the envelopes? That’s Frugal right there.

Evil: Mr. Burns from The Simpsons inspired us, right down to his finger-drumming. What’s not interesting about a guy who decides to erect a giant sky-disc to block out the sun from his town?

NeverNude: Later on in production, Grant Rodiek, Ryan Vaughan, and I became obsessed with the show Arrested Development, which led us to the Never Nude trait. We still think Tobias Funke is one of the funniest characters of all time.

An Evil Sim, scheming about pool ladders, sharks, and laser beams.

Traits for Gameplay Systems

As we fleshed out the designs for the rest of the game, we continued to add traits that enhanced the gameplay of those systems.

As we designed Fishing Skill, we added the Anglertrait – these Sims are natural fishers and have lots of fun while fishing. When designing Gardening Skill, we added Green Thumb – these Sims are great at gardening, and can even revive dead plants. And as we developed the food system, we added Vegetarian– these Sims get special versions of recipes, like Tofu Dogs, and they enjoy longer lives… but be careful: force them to eat, and they’ll start throwing up (players always enjoy new ways to torture their Sims!).

A Green Thumb

Trait Controversies

Then, there were some traits that were hard to agree upon. Do we want them? Do they fit the “Sims” style? Do they provide enough value? Here are the stories of three troubling traits:Clumsy. These Sims drop food, trip over their feet, tumble into pools, and generally lack coordination. The trouble with Clumsy was that it had no gameplay value. Some designers wondered why anyone would pick a trait that had no benefits. On the other hand, the argument was that Clumsywould be worth it just for the humor and storytelling aspects. In the end, we shipped it, and many players loved it, often saying that they themselves were clumsy, and so they felt a special attachment to it.

Kleptomaniac. These Sims have the ability to steal objects when nobody is looking. We knew the gameplay for this trait could be fun, but had a hard time agreeing on whether it had a home in the Sims universe. Sure, we’ve had burglars before. But was it okay to give players the control to steal things with their Sims? We typically avoid dark subjects. In the end, we shipped this trait with the fiction that these Sims couldn’t help it. They weren’t bad people, they just needed to steal. And players couldn't tell them what to steal -- you could only tell them to Swipe Something, and they would grab something random in the room... it could be a stereo, it could be a painting, or it could be a used toilet! We also gave them the ability to return stolen items to make amends with the victim. Kleptomaniacended up being an incredibly successful trait that helped tell some interesting stories and create funny conflicts.

Excitable. These Sims were in the same boat as Clumsy. All they did was get super-excited often, without gameplay benefit. But it was so much fun to have your Sims get excited about everyday things as mundane as checking the mail. (Excitableis actually my favorite trait.)

An excitable Sim! It’s so exciting!

The Great Merge

Eventually, we had a list of over 100 traits. Far too many. It would have been an overwhelming list for new players to wade through, and also too much to implement. First, we ruthlessly cut the weakest traits. That left us with traits that we liked, but many of them didn’t have enough gameplay, or were too similar. This led us to “The Great Merge,” where we combined a lot of our proposed traits into fewer, stronger traits with more gameplay. This eventually got us to The Sims 3’s shipping set of 63 traits.

For example:

Scientific + Genius + Gifted --> Genius

Angelic + Good --> Good

Bully + Mean --> Mean

Creative + Artistic --> Artistic

Confident + Brave --> Confident

A Genius Sim doing some calculus in the air.

Five Traits, Period.

We limit each Sim to a maximum of 5 traits. Early in pre-production, this wasn’t the case. We originally had a system where each trait had a point value, and the player had points to spend. Positive traits cost points, but negative traits returned points as an incentive to pick them, thereby allowing players to choose many traits as long as they balanced negatives with positives. But we quickly realized this approach was far too geeky and inhuman for a Sims game.

Next, we tried removing the points, and just letting players pick to their heart’s content. And that’s just what people tended to do – pick lots of traits. There’s a reason movie characters only have a few big traits – too many and it waters down their identity. We found the same thing happening in our prototype. Ultimately, we settled on a maximum of 5 as a number that was still large enough to give virtually unlimited interesting combinations, yet was small enough that each trait felt like a meaningful choice.

Also, it’s easy for players to remember 5 traits, as opposed to 7 or 10 or more. When a player can remember a Sim’s traits easily, they are more likely to change their play style in accordance with those traits – e.g. My Sim is a Virtuoso, I should practice guitar today or play in the park for tips! That’s the kind of trait-based motivation we want to see! We settled on this number even before production. You can see the space is limited to 5 trait slots in this screenshot of our 2D prototype. Testing these variations in our prototype saved us plenty of UI re-work we would have had to do if we’d learned these lessons later in production:

Our Sims 3 “Living World” Prototype, with the Create-A-Sim screen showing our 5-trait limit. This prototype helped us learn the right approaches to features like traits early on while the lessons were cheap, rather than later in production when they would be expensive.

And in the final game, it looks like this:

Looks Trump Character during Creation

We wanted to emphasize character, so we considered having traits as the very first part of Sim creation, even before the appearance of the Sim. It was a well-intentioned, but ultimately doomed idea.

We quickly learned that most players don’t even think about the internal character of their Sims until they can see the visual character. If we gave them a random Sim and opened up the traits panel, they wouldn’t pay attention to the traits – they’d feel like they needed to change the look of that Sim first.

In the end, we ordered Create-A-Sim from the most prominent physical characteristics to the least (first gender, weight, & skin tone; then hair; then face & makeup; then clothing) followed by traits. It’s interesting to note that the hair step is even before face; this is because hair makes such a huge difference in visually defining a Sim – more than setting any aspect of a Sim’s face (especially from a larger viewing distance).

The Most Popular Traits

Here are the top 4 traits:

Friendly

Athletic

Great Kisser

Family Oriented

A whopping 8% of created Sims have the Friendly trait -- yes, 8% is a considered high when there are 63+ traits to choose from, and not all Sims leave Create-A-Sim with 5 traits (younger ages get fewer). Almost as many Sims have Athletic, GreatKisser, or FamilyOriented. I love the uplifting message this sends about our Simmers – our community idealizes positive, wholesome qualities in humanity! (With a little smooching tossed in.)

A Family-Oriented Sim, gazing at her family.

We learned a strong lesson from seeing GreatKisser in the top 3. This was one of the traits surrounded by controversy about whether it had enough gameplay value to warrant its existence. All it did was give your Sims better chances of having their kisses go well with other Sims. It’s not actually a big advantage. In the world of strategy gaming, this would be a poor choice. However, Sims games don’t find their places in players’ hearts because of the strategy – instead, it’s all about the creativity, fiction, and storytelling power – and this is why GreatKisser is so popular.

Players are mostly picking traits based on the fictional character they are trying to make and not focusing on gameplay benefits as often.

In other words, they’re picking the words that best describe themselves, their ideal selves, or the people they are trying to make. GreatKissersounds awesome. Traits don’t have to have large benefits (or dev time sunk into them), but rather, they need to appeal to a player’s imaginations and aspirations first.

A Case for Negative Traits

Here are the 4 least popular traits:

Unflirty

Technophobe

Loser

Hydrophobic

It’s no surprise that the negative traits were the least popular. Unflirtywas chosen less than 0.25% of the time. After seeing this data, I often get the question about whether we should have not had negative traits. After all, what was their use if so few people pick them?

There are a few good reasons. First, they are necessary to create a diverse and challenging set of personalities for the NPCs in the town. If everyone was easy to flirt with, what fun would that be? So there’s the occasional UnflirtySim to throw a wrench in things.

Second, they can be useful in describing people we know and want to make.

Third, it allows advanced players to create more interesting challenges. Try the Legacy Challenge with a Sim who DislikesChildren, is a Loner, and Insane! And as much as possible, we tried to add benefits to the negative traits in case players decided to check them out. For example, an Unlucky Sim may burn her home down more often and get the short stick in life, but if she dies by accident or malpractice, the Grim Reaper will feel sorry for the poor Sim and resurrect her.

A Lost Trait

We couldn’t implement every trait we wanted, so I thought I'd share one of my favorites from that cut list. It's the Colorblindtrait, which I thought would be super-neat (and educational). The idea is that the player would have been able to pick a type of colorblindness for their Sim, and then when that Sim was selected, the game would use a shader to render the screen as if through colorblind eyes. Similar to this website that renders any web page (like Google) as a colorblind person would see them. A new way to see through your Sims' eyes!

A Final Word on Traits

Character Traits ended up being a very fun, easily extensible system that we’ve had a great time supplementing with each expansion. (Even before The Sims 3released, the concept of traits as an evolution of character was exciting enough that it inspired The Sims 2 team’s pet-personality system for The Sims 2 Pets.)

A Vegetarian with her trusty eggplant.

The movement from an analog personality system to discrete bundles of behavior gave us and players a creative toolbox to make millions of inspiring, deep, dramatic, and entertaining characters.

Think of some of your favorite sequels out there – Uncharted 2 or Portal 2 or Diablo 3. How do they make you feel? Sometimes it can be hard to describe what was great about a fantastic sequel, other than it was just awesome, or, phew… they didn’t screw it up!

But the recipe for a great sequel is rather simple:

1/3 The Same

1/3 Improved

1/3 New and Fresh

Once you know this, the hard work of designing a fantastic sequel becomes a little bit easier. Still an impossibly monumental task at times, but… slightly less impossible.

Playing a good sequel should be like meeting an old friend after a few years apart.Your friend has done new things; maybe he has a tattoo now or has started an exotic dog-painting business. Your friend has also (hopefully) improved himself. Maybe he’s gotten better at resisting the urge to hulk-smash creative displays of stacked food in the supermarket. But most important, your friend is still the same old person you feel comfortable being around and interacting with, and because of that, it’s only a few minutes before you’re having a great time together.

Games are no different.1/3 The SameThe most important part is that a sequel feel familiar, otherwise you risk alienating your fans. Don’t redesign aspects of your game just because you want to leave your mark on it or because you think everything has to be better.

To get started, ask yourself these questions:

What gameplay elements do your fans like best?

What are their favorite weapons, power-ups, tactics, equipment, decorations?

What characters are their favorites? What story elements elicited the strongest reactions? What inside jokes do players latch onto?

Which locations are the most iconic in your game world?

What music tracks psyche them up?

What are players sharing the most on Twitter, Facebook, and YouTube?

For example, perhaps the sniper rifle in your FPS is the weapon of choice for 45% of your players. Maybe you don’t like that balance. Maybe you feel it’s overpowered. But to change this weapon is to risk losing your loyal following. Instead, leave it the way players love it, and balance your game away from an overpowered sniper rifle through the design of your other weapons and abilities.

One area of your game that’s easy for a designer to overlook is music. Don’t neglect music! Sometimes your sound team will want to do an entirely original score. Don’t let them. Using a few familiar musical themes in your sequel can be a shortcut directly into your player’s emotions and make them feel at home instantaneously (and then they’ll be more willing to struggle to learn your “improved” UI). Every time the Legend of Zelda overworld music fires up in any of the Zelda games, things just feel right. In The Sims 3, we use some music from the original Sims game, The Sims, when your characters go into the day spa. (I wish we used more!)

Familiar settings have similar emotional effects, and can serve gameplay at the same time. The Diablo series uses Tristram in all three games – it’s the same location, but different spots in time. The player feels a familiarity, but also a sense of wonder as they experience the changes. My personal favorite example is Super Metroid, which uses some locations from the original – there’s even an energy tank in the same spot in the ceiling – but time has passed, and you get to see beyond the borders of the first game and explore the old spots in new ways. You even get to see where you first destroyed Mother Brain, which brings back a wash of memories. Instantly, you are more attached to this game. And then you find a secret below her holding tank. It’s one of my all-time favorite level-design spots in gaming:

1/3 Improved This is perhaps the easiest part of designing a sequel. It’s a designer’s natural tendency to improve all things (and this is also why the part above is so difficult).

This 1/3 of the game is all the stuff that worked pretty well in your previous installments which maybe players didn’t respond to as positively as you’d expected. Or maybe these things worked well for a while, but with added depth or tweaks, could be fantastic. Or you just need to live up to the current bar in gaming.

Here are just three examples of the features we improved in The Sims 3:

Skills. Self-improvement is a key aspect of creating compelling game characters and strong gameplay. In The Sims 3, we strived to give each level of every skill unique, obvious benefits. And we didn’t want them to end when you reached level 10, so we added achievements that would take more dedication to fulfill. For example, athletic skill has a “Marathon Runner” achievement for running 500 kilometers in the game, and the benefit is a longer life.

Create-a-Sim & Build/Buy Modes. When working on The Sims 3, we’d often walk around yelling, Customize Everything! to each other. The creativity tools are fundamental to the sandbox nature of The Sims, and we wanted to give players more control over their Sims and homes. Create-a-Sim now lets you alter details of your Sim down to custom eye color or multi-tone hair colors. Build and Buy Mode upgrades include a higher-resolution placement grid, shortcut keys to go completely off-grid as well as rotate to any angle, and place objects on surfaces. And nearly all clothing and objects let players replace their textures and then customize and save the colors in those textures.

Time Controls. I want to mention a less obvious improvement. We realized that when players fast forward in The Sims 2, often they only fast-forward a single interaction, then jump back to normal speed so they can calmly pick a new action. And they’ll bounce back and forth like this a lot. To help cater to this play style, we added a “Skip” action – which is essentially like a “next track” button on your MP3 player. It fast-forwards the Sim through the current action, then goes back to normal speed automatically, so you don’t need to try timing it yourself.

The Create-A-Style tool lets you swap materials on objects and clothing and lets you change the colors of those materials. It uses color theory to let you match multiple colors at once. In this scene, the bed is being redesigned.

1/3 New and Fresh The new stuff! This is the most exciting part of the game to design, and this 1/3 will probably take 80% of the effort. It’s a journey of good ideas, bad ideas, trial and error, play tests, and constant iteration. (And also pizza binges and one too many beach balls... yes, those are behind-the-scenes photos.)

Sometimes the next step is clear. In The Sims 3, that step was: build a seamless, clockwork neighborhood where all the Sims are living alongside you. This one big step led us to many of our other new features, which built on it, or supported it – features like collecting butterflies and gems in the world (to keep the space between homes interesting), and a “story progression” system (to keep all the other Sims aging, employed, and full of drama as time passes).

Sometimes the next step is not clear. Either way, this part must come from reflecting on your previous titles, from an awareness of your community’s desires, and from your design-filled heart.

Conclusion This recipe isn’t a magic hammer, and the proportions are just general guidelines. You’ll also still have all the hard work of actually designing the ingredients. But if you begin to think in these terms of 1/3 The Same, 1/3 Improved, and 1/3 New, you’ll be more likely to end up with a sequel that broadens your audience, makes your fans feel at home, and builds your brand into a series of hits.

One of the quandaries we had on The Sims 3 was a goal of making a deeper and more interesting game than The Sims 2, with more content to explore, but without an infinite budget and schedule (go figure).

I ran up against this wall when designing the painting skill. The Sims 2 had 12 paintings your Sim could paint on the easel (right).

I was emotionally attached to the easel because I’d programmed it in The Sims 2. It was a great object. I may have been in love with it. So I wanted to design an easel and painting skill worthy of players’ lofty expectations in The Sims 3.

To add variety, there were 3 different canvas sizes. To add depth and collectability, some paintings were uncommon and rare (known as brilliant and masterpiece paintings). To add character, certain personality Sims would paint unique variations of paintings.

And I wanted players to barely ever see the same painting twice.

By now you’re thinking, Holy Bella. That’s a metric dumpload of content… sounds insane. And you’re right. A few dozens of paintings were within scope, but each one had to be painted by a digital artist, so it took a lot of time. Here’s one of my favorites:

Every game designer has myriad sources of inspiration. But some are far more potent than others. For me, one of those inspirations is The Legend of Zelda for NES. In a way, it is soulbound to me. (I know I'm not the only one afflicted.)

So it only seems fitting that for my maiden post on game design, I reach back 23 years to my youth, when I first set foot upon the land of Hyrule.

I spent countless days wandering the lands. I held a candle to every bush. I assaulted every rock face with bombs. I pushed every tombstone. Sometimes twice, just to make sure.

In car rides I'd sit and read the manual, over and over and over. Lest you forget, this was no ordinary manual. It had a story, and it held the keys to unlocking mysteries. The manual itself was a game (expand the image on the right).

No matter how much I explored, no matter how many secrets I discovered, the land of Hyrule continued to surprise me. What?! I blew my whistle and an entire LAKE disappeared, and now there are stairs descending to a dungeon? Wow...

Because of this (and in no small part due to the early Metroid games) I highly value secrets and exploration in game design. I'm the kind of guy that rock-climbs up the edges of the map of WoW or Skyrim, crevice-jumping above the tree line, hoping to stumble on some secret alcove the designers tucked away for the boldest adventurers to find.

If there's any way I can include a secret in a game, I do. And I mean a real secret -- not a faux secret, like a wall as cracked as the Liberty Bell and (surprise) you can bomb it open. I mean the real stuff. You know it's a real secret when the player is surprised and delighted that whatever they just did... actually worked.

The first secret I put in a game was when I was a gameplay engineer on Sims 2. When a cop arrests a burglar from your home, the cop leads the thug to his cruiser, shoves him in back, then finds your Sim to say good bye. During this brief moment when the cop isn't in sight of the cop car, if you happen to click on it, an option pops up to release the burglar. Your Sim will sprint to the car, and pull out the burglar, who will then get a huge relationship bonus with you and sprint away. Of course, the cop gets pissed.

And sometimes my inspiration is more obviously linked to Zelda. Like in Sims 3: World Adventures, where one of my tomb designs under an ancient burial mound in France is reminiscent of old Zelda dungeon layouts, complete with rectangular rooms and regular patterns of statues and blocks.

Here's a slideshow:

Oh, and I made Hyrule in Sims 2 once.

Hyrule Overworld in Sims 2 Engine

Close-Up of a Map Piece

If I can craft a game that gives players the same sense of wonder, adventure, and sheer joy that I experienced playing Zelda growing up, then I have done the gaming world justice.

About the Author

I make stuff up. Creator of Merge Dragons. 10 Year vet of Maxis as Lead Designer & Creative Director on The Sims, turned indie. Now all things Merge with Gram Games! Also, a self-proclaimed mental-neurosurgeon.